Hydrocarbon liquids containing polyphenyl substituted lower alkylenes



United States Patent 3,431 094 HYDROCARBON LIQUID S CONTAINING POLY- PHENYL SUBSTITUTED LOWER ALKYLENES Arnold M. Leas, Ashland, Ky., assignor to Ashland Oil & Refining Company, Houston, Tex., a corporation of.

Kentucky No Drawing. Continuation-impart of application Ser. No. 276,865, Apr. 30, 1963. This application Jan. 23, 1967, Ser. No. 610,763 US. C]. 4480 Int. Cl. Cl1/04 9 Claims ABSTRACT OF THE DISCLOSURE The present application is a continuation-in-part of application Ser. No. 276,865, filed Apr. 30, 1963, and now abandoned.

The present invention relates to novel hydrocarbon liquid compositions, such as jet fuels, hydraulic fluids and lubricants and other crude oil derivatives. In a more specific aspect, the present invention relates to hydrocarbon liquid compositions, including jet fuels, hydraulic fluids and lubricants of improved properties, particularly, storage and thermal stability.

It is generally an accepted fact that the manufacture of jet fuels is a most demanding proposition and that any additives for hydrocarbon compositions which produce a stable jet fuel will likewise be capable of producing other hydrocarbon liquids similarly stable. Accordingly, the present discussion will be confined primarily to jet fuels with the understanding that the compositions of present invention are useful in other environments having specifications which are less stringent.

Hypothetically, the shortest distance between two points would be to connect the production nozzle of a refinery producing jet fuel to the inlet of the combustion nozzle within a jet engine. However, this is obviously physically impossible and to approach it is highly impractical. It must be recognized that refiners or producers of fuel need to blend, store, test, and schedule loading and transportation to meet the needs of a customer who, in turn, will need to store a suflicient quantity for normal usage and unexpected contingencies. In most instances, the fuel in question will have had an opportunity to accumulate contaminants during storage and transit. This fuel incipient degradation period, during storage and transit, provides time for most deleterious, dynamic physical, chemical and biological kinetic reactions to complete their offensive deterioration of the fuel. In addition, it must be recognized that fuels can vary considerably when originating from many different crude oil sources, refinery processes, shipping and storage containers, fuel handling procedures, testing procedures and additive treatments and for these reasons fail to meet specifications.

It has heretofore been proposed that the by-products of storage and/or transportation or other contaminants be removed from the fuel at the use point loading tank farm. Conventionally, a plurality of what are known as filter coalescers are used in series at the aircraft loading tank farm. However, these filter coalescers have failed to properly process supersonic jet fuels, inasmuch as such fuels must now be essentially free of soluble chemical and biological contaminants, as well as insoluble sediment and water when delivered to the aircraft; and this is a case of cure rather than prevention.

More expensive alternatives to the use of the filter coalescer, or, in addition to the filter coalescer, which have been proposed, include, over-refining at the production point, redesigning aircraft engines, speeding the fuel from the refinery in clinically clean facilities and maintaining minimal contact with oxygen during transport. Another approach is the development of additional, new all-purpose additives which will overcome the problems of origin, production, transportation and storage. It is this last approach to which the present invention is directed.

A thermally stable jet fuel is defined by the industry as a fuel which leaves no visible varnish deposits on heat exchanger metal surfaces and does not form solid particles, tending to plug jet engine fuel filters or fuel injection nozzles.

It is well known to those familiar with this art that thermal stability for jet fuels is the most demanding quality to obtain and maintain in practice, yet it is the most important property of the fuel to control.

Jet engines, and particularly the engines of supersonic and hypersonic jet aircraft, are operated at extremely high temperatures. In such use, the fuel is often used as a heat sink for the aircraft via the heat exchangers and injection nozzles in the engine. The fuel may also be subjected to elevated temperatures, during storage in wing tanks on supersonic aircraft, resulting from the absorption of heat from the surface of the wing. In some cases, the fuel may be subjected to elevated temperatures, for several hours prior to combustion, in the range of 400 to 700 F. for supersonic aircraft and to considerably higher temperatures up to the point of initiation of endothermic reactions for hypersonic aircraft. Many, if indeed not all, jet fuels tend to be relatively unstable when subjected to high temperatures below the combustion point, thus tending to form heavy solid or semi-solid particles which, in turn, cause heat exchanger fouling, jet nozzle plugging and other undesirable effects. Fuel thermal instability not only reduces the operational life of the engine but may present a hazard to flight operation. Accordingly, a very serious need to improve the thermal stability of a wide range of jet fuels has arisen.

The thermal stability of jet fuels is measured in the industry by the so-called ASTMCRC standard, modified CRC, and research CRC coker tests. In these tests, the fuel is subjected to conditions generally simulating the adverse conditions to which it is subjected in actual use. In the research coker test, for example, the fuel is heated in a reservoir to a temperature corresponding to the temperature of fuel in the aircraft wing tanks. (In the standard coker test, a heated reservoir is not used, thus, this arrangement corresponds to aircraft when the fuel is essentially at ambient temperatures in the tanks.) From the reservoir the fuel is pumped through a preheater tube at a higher temperature, corresponding to the temperature of the heat exchanger in the jet engine, and on through a filter at a still higher temperature, corresponding to the temperature at the entrance to the combustion nozzle. This filter removes non-liquid particles which have been formed at the elevated temperatures. The hot filter simulates the conditions to which the fuel is subjected as it passes through the fuel injection nozzles in the engine immediately prior to combustion. The operating conditions of the test can be varied to correspond to various use conditions. Coker test conditions are usually expressed in abbreviated form; for example, 200-400/ 500/ 6 meaning that the reservoir temperature is 200 F., the preheater temperature 400 F., the filter temperature 500 F., and the fuel flow rate 6 pounds per hour.

At the present time, fuels to be used in Mach 3 plus jet aircraft utilize coker conditions of 300500/600/6, and, in the future, it is expected that these conditions will be further increased in severity to 300600/ 700/ 6.

The results of the coker tests are expressed in terms of a rating code, indicating relatively the quantity of varnish deposit left in the preheater, ranging from for the best, to 8, for the worst, and in terms of the pressure drop in inches of mercury across the filter, ranging from O, for the best, to 25 inches for the worst. The high thermal stability demanded of Mach 3 plus jet fuels is indicated by the fact that they must have a preheater code rating less than 3 and a filter drop of less than inches of mercury.

It is therefore an object of the present invention to provide a hydrocarbon liquid composition which solves all of the above-mentioned problems. Another object of the present invention is to provide a new group of additives for liquid hydrocarbons, particularly jet fuels, hydraulic fluids and lubricants. Still another object of the present invention is to provide a new group of the present invention is to provide a new group of additives for hydrocarbon liquids, including jet fuels, hydraulic fluids and lubricants which are suitable for use either at the point of production or at the point of use. A still further object of the present invention is to provide a new group of additives capable of converting a good hydrocarbon liquid, particularly aircraft fuel, into a better quality product. Another and further object of the present invention is to provide a new group of additives for hydrocarbon liquids, particularly aircraft fuels, which will permit the use of hydrocarbon products from a wide variety of crude oil sources; which have been subjected to a wide variety of refining processes; which have been shipped and stored in a large number of different containers; and which have been subjected to a large number of different handling procedures, test procedures and additive treatments. A further object of the present invention is to provide an improved hydrocarbon liquid composition suitable for use as aircraft fuels which will result in a minimum rejection of fuels and make possible maximum in-flight safety with minimum tankage and inventory at the point of use. A still further object of the present invention is to provide a new group of additives for hydrocarbon liquids, particularly aircraft fuels, hydraulic fluids and lubricants which produce a thermally stable product. These and other objects and advantages will be apparent from the following detailed description.

In accordance with the present invention, it has been found that the degradation of hydrocarbon liquids can be reduced, particularly during transportation and storage,

and the thermal stability of such hydrocarbon liquids, at moderately high temperatures can be improved by the addition of polyphenyl substituted lower alkanes and polyphenyl substituted lower alkylenes to the hydrocarbon liquid.

While the invention will be described primarily with relation to jet fuels, it is to be understood that the present additives are equally effective in other hydrocarbon liquids such as hydraulic fluids, lubricants, base fuels, and, to some extent, in hydrocarbon solvents and other chemicals.

The substituted phenyl compounds used in accordance with the present invention include alkyl-substituted phenyl compounds, such as, diphenylmethane; triphenylmethane; 1,1,2-tri-phenylethane; 1,1,2,2-tetraphenylethane, etc. and alkylene-substituted phenyl compounds, such as, 1,2-diphenylethylene; 1,1,2,Z-tetraphenylethylene; etc.

The subject additives are utilized in concentrations of about 0.0001 to 0.1 percent by weight of the hydrocarbon iquid.

It has been found that these new additives are particularly effective in minimizing the rate of fuel degradation prior to use of the fuel. Accordingly, these additives are preferably added to the hydrocarbon liquid, particularly jet fuels, before storage at the refinery, before transportation from the refinery to the use point or before storage at the use point. These hydrocarbon liquids, particularly fuels, are transported or stored for a significant period of time, these liquids tend to oxidize to some extent and thereby produce oxygenated impurities, even at ambient temperatures. These oxygenated impurities are extremely detrimental to the hydrocarbon liquid and particularly to fuels for use in jet aircraft.

Preferably, any oxygenated compounds which do form in spite of the addition of the novel stabilizers of the present invention should be removed prior to use of the fuel. This can be accomplished by certain filtration techniques, preferably through a solid, adsorbent media.

The thermal stability of fuels can be measured by the coker ratings of the fuel as previously described. The value of the additives of the present invention are illustrated by the following examples.

ASTM-CRC COKER DATA WITH VARIOUS TREATMENTS WITH AND WITHOUT ADDITIVES, WITH AND WITHOUT FILTRATION WHEN USING JP-5 TYPE JET FUELS Coker 300/400/6 Dirt Preheater Pressure content,

rating drop, mg./gallon code No. in. Hg

(1) JP-5: N o additive, no filtration 5 25 9.4 (2) 119-5: 0.005% diphenylmethane no filtration 3 25 10. 7 (3) JP5: 0.005% diphenylmethane,

with filtration. 2 0.7 1. 4 (4) JP-5: 0.005% triphenylmethane,

no filtration I. 0 25 12. 4 (5) JP-5: 0.005% triphenylmethane,

with filtration 2 1. 4 2. 6 (6) .lP-5: 0.005% 1,2 diphenylethylone, no filtration 4 25 10. 9 (7) JP-5z 0.005% 1,2 diphenylethylone, with filtration 1 0 5 0.8 (8) JP-5: 0.005% 1,1,2,2 tetraphenylethylene, no filtration 7 25 7. 0 (9) ZIP-5: 0.005% 1,1,2,2 tetraphenylethylene, with filtration 2 1. 3 1. 1 (10) JP-5: 0.005% 1,1,2 triphenylethane,no filtration 8 25 15. 6 (11) JP-5: 0.005% 1,1,2 triphenylethane, with filtration 3 1. 6 1. 3 (12) ZIP-5: 0.005% 1,1,2,2 tetraphenylethane, no filtration 6 25 11. 2

3) JP-5: 0.005% 1,1,2,2 tetraphcnylethane, with filtration 1 0. 8 0.7

N0rr;.Filtration was made through 2 feet of Attapulgus type clay (30-60 mesh).

I claim:

1. An improved thermally stabilized hydrocarbon liquid composition comprising a major proportion of a hydrocarbon liquid and 0.0001 to 0.1 percent by weight of the total hydrocarbon liquid of a thermally stabilizing compound selected from the group consisting of polyphenyl substituted lower alkane and polyphenyl substituted lower akylene.

2. A composition in accordance with claim 1 wherein the hydrocarbon liquid is a freshly produced hydrocarbon liquid which has not been subjected to any significant period of storage.

3. A composition in accordance with claim 1 wherein the hydrocarbon liquid is a jet fuel.

4. A composition in accordance with claim 1, wherein the polyphenyl substituted lower alkane is diphenyl methane.

5. A composition in accordance with claim 1, wherein the polyphenyl substituted lower alkane is triphenyl methane.

6. A composition in accordance with claim 1, wherein the polyphenyl substituted lower alkane is 1,1,2-triphenyl ethane.

7. A composition in accordance with claim 1, wherein the polyphenyl substituted lower alkane is l,1,2,2-tetraphenyl ethane.

8. A composition in accordance with claim 1, wherein the polyphenyl substituted lower alkylene is 1,2-diphenyl ethylene.

9. A composition in accordance with claim 1, wherein the polyphenyl substituted lower aikylene is 1,1,2,2-tetra- DANIEL WYMAN, Primary Examine?- phenyl ethylene. WILLIAM J. SHINE, Assistant Examiner.

References Cited S C 5 U. 1. X.R. FOREIGN PATENTS 252 59 78 735,134 8/1955 Great Britain. 

